This invention relates generally to hydrotherapy and more particularly to hydrotherapy jet assemblies intended for installation in the walls of water tubs, typically referred to as spas, hot tubs, jetted bathtubs, etc.
Applicants' parent application Ser. No. 064,138 discusses the common use of ambient air entrainment in conventional hydrotherapy jet assemblies to discharge a high velocity water/air stream for the dual purpose of creating turbulence in the tub water pool and impacting against a user's body. The application points out that air entrainment unfortunately lowers the pool water temperature and thus frequently requires heater intervention and/or hot water replacement to maintain user comfort. In order to avoid this, and additionally to reduce the noise level characteristic of conventional hydrotherapy jet assemblies, applicants' parent application discloses an improved jet assembly which utilizes tub water entrainment, rather than air entrainment, to produce the discharge stream. The assembly is characterized by the inclusion of a passageway communicating the tub water with a mixing chamber within the assembly. This allows a high pressure water jet supplied to the mixing chamber to entrain the tub water for discharge into the tub through a tubular flow director, more typically referred to as an "eyeball".
The preferred embodiment disclosed in applicants' parent application includes a manually adjustable valve member which enables the user to vary the amount of tub water entrained by the supplied water jet to thus adjust the intensity of the discharge stream.
Certain prior art air entrainment jet assemblies also include means for adjusting the discharge stream intensity, e.g. by varying the amount of jet water supplied and/or the amount of air available for entrainment. One such jet assembly is disclosed in U.S. Pat. No. 4,541,780 which teaches controlling the flow of water and air by controlling the movement of a single valve mechanism. A feature of that assembly is that the air passageway can never be significantly opened when the water supply passageway is not opened sufficiently to create a lower pressure in the mixing chamber than is present in the air supply line. This avoids malfunction when multiple assemblies are coupled for ganged operation.